The monarch is due to attend the event at Glasgow Cathedral on August 4 next year. The city has been chosen as a focal point for activities to mark the start of the conflict, as it is hosting the Commonwealth Games which end the day before.

Across the country, flags on public buildings will fly at half mast on the anniversary of the outbreak, while, in Belgium, another service will be held at St Symphorien Military Cemetery near Mons, where similar numbers of British and German war dead are buried, including the first and last Commonwealth soldiers killed in the conflict.

The day will end with a vigil at Westminster Abbey where a single candle will be extinguished at 11pm, a century on from the moment when, in the words of Sir Edward Grey, Britain’s foreign secretary at the time, “the lamps are going out all over Europe”.

Tomorrow, ministers will announce details of the entire programme from 2014-2018, which they hope will allow people to mark the conflict which ravaged the continent “with sorrow and with pride”.

Nearly 10 million soldiers were killed before the guns finally fell silent on Armistice Day, 11 November 1918.

The same date in 2018 will also see flags at half mast on public buildings, ministers are expected to confirm tomorrow, along with a new £10 million funding for art, drama and music projects linked to the conflict.

The candlelit vigil at the Abbey – to be attended by scouts, cubs and brownies as well as members of the Armed Forces – will, it is hoped, be replicated around Britain in churches, town halls, and other venues.

A government source said last night: “We are keen to ensure that this a centenary programme that the country can come together on.”

Other events being organised for next August include the recreation of the mobilisation of the Royal Flying Corps, the precursor to the Royal Air Force.

Under plans being drawn up by the Western Front Association, replica biplanes from the conflict will recreate the flight, on August 13, of three squadrons which took off from airstrips near Dover and landed in France, near St Omer.

One machine, an SE5, has already been identified, but organisers hope that other aircraft from the period will also take part. RAF aircraft may accompany the vintage replicas, with discussions under way which could see the Red Arrows complete a fly-past over the former battlefields.

Another “centrepiece” events next August, is likely to be the unveiling of a new memorial arch being built in Folkestone, the port from which most soldiers departed for the Western Front.

The arch will be on a hill leading down to the harbour, a route along which the men marched to the waiting transport ships. Money is being raised as part of a project called “Step Short”, named after the command which was given to marching soldiers to allow them to negotiate the slope in an orderly fashion.

Further major events will follow until the centenary of the end of the conflict, in 2018. One of the most spectacular could be one planned by the Royal Navy to mark 100 years since the Battle of Jutland, in 2016.

It is understood the anniversary will centre on Scapa Flow, in the Orkney Islands, from which the British Grand Fleet departed to head for their clash with the German High Seas Fleet off the coast of Denmark. The event could involve modern warships from a number of navies.

Government plans also include sending a delegation from every state secondary school in the country to visit battlefields.

Ministers hope the commemorations will harness the patriotic spirit which came to the fore last year with the twin celebrations of the Olympic Games and the Queen’s Diamond Jubilee, when the country wrapped itself in the Union Flag.

Senior figures in the government are also crossing their fingers that the First World War programme gives a political boost to the campaign for a “No” vote in next year’s referendum on Scottish Independence. August 4 next year, the start of the commemorations, is just over six weeks before the independence vote north of the border, which will be held on 18 September.

Alex Salmond, Scotland’s First Minister, got in ahead of David Cameron by announcing a separate programme to commemorate the conflict last month.

This centres around battles in which large proportions of troops from north of the border served, such as Loos, in 1915, and Arras in 1917, as well as other events closer to home such as the Quintinshill train crash, in 1915, near Gretna, when 214 servicemen were killed, and the loss of HMS Iolaire, which was carrying servicemen back to Lewis after the war, when it sank with the loss of 205 men.

Groups in Wales are also organising specific events, including commemorations for the Battle of Mametz Wood, part of the Battle of the Somme, in which the 38th (Welsh) Division fought.

Other Welsh commemorations will have a particularly literary flavour: The Welsh National Opera is to perform a new opera based on “In Parenthesis”, a poem about the battle by David Jones, while another major anniversary event will be the 2017 Eisteddfod.

This will mark 100 years since the so-called Black Chair Eisteddfod, at which the judges announced that the winner of the “Chairing of the Bard” event was Hedd Wyn, the poet, but that he had been killed a month earlier during the battle of Passchendaele.

The chair he was to have sat in was draped in black cloth. There will also be a particular focus on the Welsh miners who dug extensive tunnel networks along the Western Front, and David Lloyd George, who was prime minister from 1916.

Throughout the country, local groups are coming up with their own ways of marking 100 years since the conflict. Many of these have been featured in The Sunday Telegraph’s ongoing our Lest We Forget campaign, launched to ensure war memorials are in a fitting state for the centenary.

Tomorrow’s announcement will be the culmination of several months work by the government’s advisory board, which includes senior retired military figures, politicians, writers, historians and religious leaders.

The group was charged with putting together the programme of events and “educational initiatives”, with £50 million from government and National Lottery funds supporting the commemorations.

Bonnie Greer, the playwright and author has joined the panel to, in the words of a source, enhance the “theatrical” and “spectacular” aspects of the plans.

She said commemorations should be more than just events to mark the anniversaries of the war’s major events.

“We know so much about the conflict in terms of the big set pieces. We need to know what it was like for people who thought the war would be over by Christmas and who found out it wasn’t, for those towns who lost all their young men.”

Ms Greer, whose father served in the Second World War, added: “World War One has always been the war that has interested me the most as it was the war that influenced the world the most.

“My personnel connection has to be with the fact that my dad was from the Deep South and US African Americans came back from Europe and began the change that led to the Civil Rights movement.”

The panel will meet for the third time later this week when officials from the Foreign and Commonwealth Office will update members on what other countries are preparing. Plans in Australia and New Zealand, in particular, appear to be much further advanced than those in the UK.

A government source said: “We have seen in recent years that communities across the UK are really at their best when they are brought together with feelings of patriotism and history. We saw this with the Jubilee, the wedding of the Duke and Duchess of Cambridge and the Olympics.

"We’re sure that British communities will come together throughout the centenary programme in all sorts of different ways, to reflect and remember the huge sacrifice that so many people made.”

Maria Miller, the Culture Secretary, said: “The Great War saw huge suffering and enormous sacrifice and our centenary programme will mark it with both sorrow and pride as is fitting.

"Those four years changed British society forever and it is absolutely vital that we all remember the price paid.

“At 11pm on the 4th August 1914 it was said that 'the lamps are going out all over Europe’; 100 years later we will extinguish the last candle in Westminster Abbey to commemorate that hour as a mark of respect and remembrance that will set the tone for the events to come.”